RU2228567C1 - Multifrequency vibration damper - Google Patents

Abstract

FIELD: power engineering; overhead power transmission lines and communication lines. SUBSTANCE: vibration damper has counterpoises and clamp that secures damper for instance to power transmission line conductor. Rod-type counterpoises have one part joined to ground wire and other, longer, part can be turned by bending through definite angle relative to ground wire. The latter carries bushing joined to short part of rod. Vibration damper is designed as multifrequency device that can function at frequencies corresponding to a number of resonance peaks of bending and torsional vibrations due to varying length of rods, and adequate selection of their disposition on ground wire makes it possible to ensure effective vibration damping on line cables (conductors). EFFECT: simplified design and facilitated manufacture of vibration damper. 4 cl, 7 dwg

Description

The invention relates to the field of electric power, in particular to vibration dampers mounted on wires of overhead power lines or on self-supporting fiber-optic cables of communication lines.

Known multi-frequency vibration damper for the wires of an overhead power transmission line, comprising an elastic damper element made in the form of a steel wire rope, cast weights rigidly fixed at an unequal distance from the damper suspension point at the ends of the damper element, and made in the form of a clip equipped with a hook of the housing and the die the clamp is fixed by crimping on the middle part of the elastic damper element, and the clamp hook is attached to the wire by means of a die with a bolt and nut [1].

As you know, the frequency range of the aeolian vibration of various protected objects (wires of power lines, optical cables) is quite wide (from 5 to 100 Hz) and can hardly be completely covered by an inertial damper of one standard size. Therefore, usually a number of vibration dampers are simultaneously developed to provide vibration protection for a large number of objects. To change the operating frequency range of the vibration damper, it is necessary, as a rule, to change not only the length of the elastic damper element (cable), but also the mass and mass distribution of the goods along their length. Obviously, in the case of using cast loads, it will be necessary to develop and cast new loads of a different configuration. In addition, the complex and time-consuming technology of securing the clamp and weights on a steel cable, for example, by pressing in loads using intermediate sleeves or pouring with molten metal, due to the large thickness of the load at the place of its installation on the damper element, implies the use of various expensive technological equipment, which leads to increase the cost of the damper and reduce its competitiveness in the market.

The closest technical solution in relation to the proposed one is an easy-to-manufacture and cheap multi-frequency vibration damper for overhead power lines and self-supporting fiber-optic cables of communication lines, containing an elastic damper element made in the form of a steel multi-wire cable, loads of various weights, made in the form bent rods rigidly fixed by one of their ends at the ends of the cable coaxially with it, and a clip for suspension on a wire, fixed at one end to the middle parts of the cable are asymmetrical to the points of fastening of the cargo, while others are attached to the wire [2].

This vibration damper with obvious manufacturability also has several disadvantages. This technical solution makes it difficult to optimize the distribution of mass along the length of the cargo, since the cargo actually has only one linear dimension - the length of a constant value with a relatively small linear mass (the diameter of the bar is limited by the technological simplicity of bending the bar and securing it to the damper element). However, it turns out to be impossible to obtain low resonant frequencies with the required distribution of these frequencies in the operating frequency range of the damper. In addition, the die mount of the vibration damper on the wire (cable) and the need to make a molded case and clamp die increase the cost of its construction.

The authors solved the problem of developing the design of a cheap vibration damper, capable of changing its frequency range of vibration damping with a minimum of technological operations in a wide range of resonant frequencies of aeolian oscillations (from 5 to 100 Hz), characteristic of overhead power transmission wires and self-supporting fiber-optic communication cables. The latter is achieved due to a combination of essential features, namely: a multi-frequency vibration damper for overhead power transmission wires and self-supporting fiber-optic communication cable cables, comprising an elastic damper element made in the form of a multi-wire steel cable, loads of various weights made in the form of curved rods, rigidly fixed by one of its ends at the ends of the cable coaxially with it, and a clip for the suspension on the wire, fixed at one end on the middle part of the cable is asymmetrically rel relative to the points of cargo fastening, and the other fastened to the wire, and each of the goods, bent in the middle part at an angle of 150 ... 310 °, is equipped with at least one sleeve rigidly fixed on the straight part of the rod with an inner diameter equal to the diameter of the rod cargo, and the plane of the bend of the rod is deployed relative to the plane of the suspension at an angle of 30 ... 60 °, and the damper clip is made in the form of at least two rigidly fixed to the cable and attached to the wire S-shaped plates, offset from the middle of the cable 10 ... 20% of e th total length; these bushings are installed on one of the straight parts of the rods connected to the cable in such a way that their free parts face the clamp side, and the free part of each sleeve has an elliptical cross section, with the major axis of the ellipse inclined to the plane of the suspension at an angle of 15 ... 45 ° ; the bushings are mounted on cylindrical clips rigidly fastened to the rectilinear part of the cargo rods; S-shaped plates mounted on opposite sides of the suspension point are rotated 180 ° and interconnected by a rigid jumper.

The invention is illustrated by drawings, where in Fig.1 is a General view of a multi-frequency vibration damper, made according to the present invention, a front view perpendicular to the wire (cable) line; figure 2 - the same vibration damper, side view (along the axis of the wire); figure 3 is a section along the arrows BB in figure 1; figure 4 is a variant of the proposed damper, made according to claim 3 of the claims; figure 5 is an axonometric view of the load, the rods of which are bent at a certain angle of bending; figure 6 is a variant of the proposed damper, made according to claim 2; Fig.7 is a view along arrow A in Fig.6.

The vibration damper for the wires of overhead power lines and self-supporting fiber optic cables 1 of the communication lines consists of an elastic damper element 2, made in the form of a piece of steel cable, at the ends of which weights 3 are fixed. In the middle part of the cable 2, a clip 4 is fixed, with which a damper suspended on a wire (cable) 1.

The elastic damper element 2 is a steel cable made of spiral wires of high strength steel, which are fixed with their ends in each of the weights 3. The optimal number of spiral wires included in the set of element 2 is 19 pieces. Spiral wires are in a stress-strain state, which is ensured by their twisting followed by crimping with an appropriate tool. With this manufacturing technology, the elastic damper element 2 provides high energy absorption during deformation.

Cargoes are curved rods made of a bar with short 5 and long 6 straight parts. The short part 5 loads 3 are mounted drilled in them coaxial hole 7 on the elastic damper element 2 and are fixed on it (for example, by crimping). Cargoes 3 differ from each other in mass. The bending of the rods in the manufacture of goods 3 is performed in the plane (for angles β≤180 °), or along a helix 8 at 180 ° <β≤310 ° (see figure 5). In the latter case, the bending of the rod can also be considered flat with some approximation, taking for the plane of the bend the plane passing through the centers of the ends of the rod and the middle of the bent section. When installed on the cable 2 vibration damper, the plane of bend 9 of each rod 3 of the goods is rotated relative to the plane of the suspension of the vibration damper at an angle γ = 30-60 ° (see figure 2). The plane of the suspension is a vertical plane passing through the longitudinal axis of the wire (cable) 1 (Fig. 2 shows a section of this plane, position 4).

Additional weights in the form of bushings 10 are also introduced into the design of the vibration damper. The inner diameter of the bushings 10 is chosen approximately equal to the outer diameter of the rods (weights 3), and each of the bushings 10 is rigidly fixed (pressed) on the long 6 or short 5 straight part of the load 3. B the latter case, free, that is, not participating in the fastening on the load 3, part 11 of the sleeve 10 is deployed in the direction 4 of the vibration damper. The free part 11 of the sleeve 10 can be made elliptical in cross-section with an angle of inclination α of the major axis 12 of the ellipse to the plane of the suspension of the vibration damper from 15 ° to 45 ° (see Fig.6, 7). On the short part 5 of the rod 3, a cylindrical ferrule 13 can be fixed, on which, in turn, the sleeve 10 is attached.

The vibration damper clamp 4 consists of several parts, in particular, S-shaped plates (two or more plates) that can be connected by a hard jumper 14. The plates can be mounted on different sides of the suspension point 15 and rotated 180 °. The suspension point 15 is located on the longitudinal axis of the wire (cable) 1 in the middle of the clamp 4, fixed on the wire (cable) 1 (see figure 1).

The vibration damper is mounted on the wire (cable) 1 and fixed on it with a spiral clamp (not shown). The locations of the vibration dampers on the wires (cables) of 1 lines are determined by calculation or experimentally.

The proposed multi-frequency vibration damper operates as follows. When a vibration line occurs in the span that is close in frequency to the resonant frequencies of the vibration damper weights, vibrations of the damper parts are excited, i.e. sections of the damping element 2 (cable) with loads 3. In this case, a significant part of the energy is dissipated in the form of heat on the surfaces of the rubbing wires of the elastic damper element.

The damping of vibrations in each part of the vibration damper occurs at frequencies corresponding to the first three resonant forms of bending-torsional vibrations of the load - elastic damper element of this part of the load rod. Higher forms, as a rule, are not excited and are usually outside the mentioned frequency range.

The lowest resonant frequency of each part of the vibration damper load is determined by the length of the cable and the mass of the load. The second and third resonant frequencies - the length of the cable and the distribution of mass over the volume of the cargo. In order to ensure reliable operation of the damper in a given frequency range, it is necessary to ensure the correct distribution of the resonances of the parts of the vibration damper load in this range. By changing the lengths of the short 5 and 6 long parts of the rods 3 and the length and number of bushings 10, as well as changing the location of the clamp 4 on the elastic damper element 2 and the location of the bushings 10 on the loads 3 relative to the plane of the vibration damper’s suspension, it is possible to optimize the number and distribution of resonance peak frequency-amplitude vibration damper characteristics and, therefore, increase the degree of vibrational protection of wires of overhead power lines and fiber optic cables of communication lines. The bushings 10 can be installed on the long and short rectilinear parts 5, 6 of the rods 3. In the latter case, the sleeve 10 can be mounted on the rod 3 so that part of it, facing toward the clamp 4, does not rest on the rod 4. Moreover, part 11 of the sleeve 10, located above the cable 2, is elliptical in cross section, which allows for a greater range of free oscillations of the load 3 on the cable 2. To increase the gap between the cable 2 and the sleeve 10 between the rod 3 and the sleeve 10 can also be installed cylindrical cage 13, the presence of Torah also increases the weight of the load 3.

Clamp 4, made of at least two S-shaped plates rotated 180 °, allows for convenient installation of a vibration damper on a cable / wire. During installation, a vibration damper is deployed across the wire, wound on it and rotated along its axis. As a result, the upper ends of the S-shaped plates cover the surface of the cable / wire. In this position, the vibration damper is secured with pieces of wire spiral covering the upper ends of the S-shaped plates and the surface of the cable / wire.

The inventive vibration damper has a set of positive characteristics, namely, it can operate in a wide frequency range of resonant oscillations characteristic of overhead power lines and fiber-optic communication lines; the dependence of the energy dissipated by this damper on the frequency of vibrational vibrations is more acceptable from a practical point of view than the same dependence of the known damper for a similar purpose; structurally, the absorber is made quite simply and, in addition, it is technologically advanced in manufacture; no special costs are required for the organization of serial production of the proposed multi-frequency vibration dampers.

Sources of information

1. US patent N4159393, CL.174-42 (H 02 G 7/14), 06/26/1979.

2. US patent N3400209, CL 174-42 (H 02 G 7/14), 09/03/1968.

Claims (4)

1. A multi-frequency vibration damper for wires of overhead power lines and self-supporting fiber-optic cables of communication lines, comprising an elastic damper element made in the form of a multi-wire steel cable, loads of various weights, made in the form of curved rods, rigidly fixed by one of their ends to the ends of the cable coaxial with it, and a clip for suspension on the wire, fixed at one end on the middle part of the cable asymmetrically with respect to the load securing points, and the other fixed to the wire, characterized I mean that each of the goods, bent in the middle part at an angle of 150 ÷ 310 °, is equipped with at least one sleeve rigidly fixed on the rectilinear part of the rod with an inner diameter equal to the diameter of the cargo rod, while the plane of the bend of the rod is turned relative to the plane suspension at an angle of 30 ÷ 60 °, and the damper clamp is made in the form of at least two S-shaped plates fixed to the wire and attached to the wire, offset from the middle of the cable by 10 ÷ 20% of its total length. 2. The damper according to claim 1, characterized in that the bushings are installed on one of the ends of the rods connected to the cable with straight parts of the rods in such a way that their free parts are facing toward the clamp, while the free part of each sleeve has an elliptical cross section and a large axis the ellipse is inclined to the plane of the suspension at an angle of 0 ÷ 45 °. 3. The damper according to claim 1, characterized in that the bushings are mounted on cylindrical clips rigidly fastened to the rectilinear part of the cargo rods. 4. The damper according to claim 1, characterized in that the S-shaped plates mounted on opposite sides of the suspension point are rotated 180 ° and interconnected by a hard jumper.

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